Various systems for Local Area Networks are known from the prior art. However, these systems are all based on a particular medium and other particular standards which pose significant problems in the field.
The LAN standards in existence that pertains to this disclosure are listed below.
Digital Equipment Corporation/Intel/Xerox Ethernet.TM. Version 2.0
ISO/ANSI/IEEE 802.3 CSMA/CD,
ISO/ANSI/IEEE 802.4 Token Bus
ISO/ANSI/IEEE 802.5 Token Ring
ISO/ANSI X3T9.5 FDDI (Fiber optic Distributed Data Interface), a Token Passing Ring.
All of the above are networking protocols, and each standard specifies the Media Access methods (MAC), and Logical communication Link Control methods (LLC).
The concept of the "backplane bus" is well established in the computer and communications field; examples of standardized and proprietary backplane buses abound. In the most general terms, a backplane bus is a wiring center common to a single platform and shared by a number of users (generally implemented as printed circuit boards plugged into the bus via a single connector).
The backplane bus is generally used for communications between the users according to some common protocol. Prior art arrangements in this field require that the bus be dedicated to a single bus access protocol, and that all users of the bus communicate across the bus using only this protocol.
The protocol consists of an access method, data format and data rate, all of which must be common to all users of the bus. In general, only one user of the bus may generate data "packets" onto the bus at any instant; access to the bus is governed by a distributed mechanism common to all users of the bus, termed the access method.
Specifically in LAN applications of backplane buses, there are two well established access methods: Carrier Sense, Multiple Access with Collision Detection (CSMA/CD) and Token Passing. Token passing further distinguishes to a physical ring and physical bus manifestation. All of these access methods are used with multiple data rates and data formats, generating numerous protocols; in addition, there are other protocols which combine elements of both CSMA/CD and Token Passing, as well as protocols which use only some elements of the access methods (e.g. Carrier Sense, Multiple Access without Collision Detection).
Prior art in this field provides a single, unique backplane bus designed specifically for a single protocol. An example of an implementation of a single protocol backplane bus is found in the Multiconnect.TM. Repeater from 3Com Corporation. This product offers a backplane bus dedicated to the IEEE 802.3 10 MegaBit/Second CSMA/CD protocol (commonly known as Ethernet.TM.).
Additional prior art in this field provides multiple unique, separate backplane buses, each of which is specifically designed to support a single protocol. An example of this implementation is found in the System 3000.TM. Wiring Concentrator from Synoptics Corporation. This product offers four independent backplane bus protocols, each dedicated uniquely to one of the following protocols:
1. IEEE 802.3 10 Megabit/Second CSMA/CD (Ethernet.TM.)
2. IEEE 802.5 4 Megabit/Second Token Passing Ring
3. IEEE 802.5 16 Megabit/Second Token Passing Ring
4. ANSI X3T9.5 100 Megabit/Second Token Passing Ring (FDDI)
Additional prior art arrangements in this field provide a single backplane bus implementing a single protocol, and require the users of the bus to support protocol conversion between external multiple protocol interfaces and the internal protocol. All of these prior art arrangements suffer from the following limitations:
1. The backplane bus is dedicated to a single protocol, allowing no flexibility for growth or change.
2. The backplane bus supports only a single data path, allowing only one data packet to be generated onto the bus at any time.
3. Attempts to address these limitations in the prior art lead to higher costs: additional backplane buses or complex protocol converters (e.g. network bridges).
4. Each module within a system cannot be operating independently from the backplane network.
The concept of the logical network and the physical network configuration has been only attainable through a physical embodiment of physical network connections. All of the LAN/WAN (Local Area Network/ Wide Area Network) networking hub implementations are dedicated to, a single protocol, or to dedicated protocol channels to interconnect network users. By this pre-determined use of backplanes and their functional and physical definitions, the concept of module switching among generic channels was not possible.
Arrangements providing similar functions are known. The Access One.TM. from Ungermann-Bass, System 3000.TM. from Synoptics, MMNC.TM. from Cabletron, Multiconnect.TM. from 3Com corporations are examples of prior art arrangements.
Access One.TM. from Ungermann-Bass, System 3000.TM. from Synoptics, MMAC.TM. from Cabletron, Multiconnect.TM. from 3Com all employ dedicated protocol channels, and most offer one protocol and one channel only.